I have a Clifford alarm system on my motorhome. Both front doors and the back door have sensors, there is a motion sensor and glass breakage (noise)sensor. I have it wired to the house batteries and the unit has a 9 volt battery back-up. It has been in place for 29 years. Occasionally there will be a false alarm because of high wind or a loud noise near the motorhome, but for the most part it has been foolproof.
I had to replace the siren about 10 years ago. It chirps when armed or disarmed, and quit working.
I have a 30 amp outlet on a timer from Lowes that charges my house batteries for one hour a day. There is also a trik-l-charge that charges the coach battery at the same time.
This has been a good alarm system. I would buy another one.